Обсуждение: Warm/hot backup server question

Hi,

I've been given the job of creating a hot/warm backup server
for a live Postgresql server.  The problem is two-fold: 1) it's version
7.4.9 and an upgrade is not feasible at this time and b) there are
multiple instances of postgresql running on the box; not multiple
databases, multiple *servers*, each listening on a different port (it
was a business requirement from what I've been told).

I plan on using heartbeat and mon to monitor the primary server for
non-availability and fail over.

I thought about DRBD, but that would require repartitioning the live
server and I want to touch it as little as possible.

I've read the docs for WAL and the 8.2 version sounds perfect for what
I want but, as I said, an upgrade is out of the question for now.  I
see that 7.4 has WAL, but I didn't see mention of the warm backups as
mentioned in the 8.2 docs.  Can 7.4 do the same magic as 8.2 wrt to
WAL?

Is SLONY/replication my only choice?  Remember, I can't/don't want to
rebuild the existing servers.

TIA!

--

Regards,

Faber Fedor
President
Linux New Jersey, Inc.
908-320-0357
800-706-0701

http://www.linuxnj.com




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"Faber J. Fedor" <faber@linuxnj.com> writes:
> I've been given the job of creating a hot/warm backup server
> for a live Postgresql server.  The problem is two-fold: 1) it's version
> 7.4.9 and an upgrade is not feasible at this time and b) there are
> multiple instances of postgresql running on the box; not multiple
> databases, multiple *servers*, each listening on a different port (it
> was a business requirement from what I've been told).

If they won't let you update to 7.4.18 (the current release in that
branch), you would be best advised to resign at once, before you get
blamed for the train wreck that is inevitably in this system's future.
7.4.9 is two years old, and I count at least six fixes since then for
data-loss bugs of the *will*-bite-you-eventually type; plus a couple
more that you might be at risk for depending on which features you use.
Also, the choice to run separate servers sounds a whole lot like they
are serving clients that they don't trust 100%, which means there are
also half a dozen security fixes that they should be worried about.

> Can 7.4 do the same magic as 8.2 wrt to WAL?

No.  Slony is your best bet --- not least because it may simplify a live
upgrade to a newer version.

            regards, tom lane

On 10/7/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Faber J. Fedor" <faber@linuxnj.com> writes:
> > I've been given the job of creating a hot/warm backup server
> > for a live Postgresql server.  The problem is two-fold: 1) it's version
> > 7.4.9 and an upgrade is not feasible at this time and b) there are
> > multiple instances of postgresql running on the box; not multiple
> > databases, multiple *servers*, each listening on a different port (it
> > was a business requirement from what I've been told).
>
> If they won't let you update to 7.4.18 (the current release in that
> branch), you would be best advised to resign at once, before you get
> blamed for the train wreck that is inevitably in this system's future.
> 7.4.9 is two years old, and I count at least six fixes since then for
> data-loss bugs of the *will*-bite-you-eventually type; plus a couple
> more that you might be at risk for depending on which features you use.

I agree.  Although I'd set up your new job first if possible.

I also agree that Slony is your best bet.  Note only the older
versions of slony run on 7.4, so make sure you download the version of
slony that works with 7.4.  I think it's 1.0, could be 1.1 or so.

On 07/10/07 21:42 -0400, Tom Lane wrote:
> If they won't let you update to 7.4.18 (the current release in that
> branch), you would be best advised to resign at once, before you get
> blamed for the train wreck that is inevitably in this system's future.

Done.

Now, how are you on giving advice to improve my love life? :-)

--

Regards,

Faber Fedor
President
Linux New Jersey, Inc.
908-320-0357
800-706-0701

http://www.linuxnj.com




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On Mon, 8 Oct 2007 21:34:10 -0400
"Faber J. Fedor" <faber@linuxnj.com> wrote:

> On 07/10/07 21:42 -0400, Tom Lane wrote:
> > If they won't let you update to 7.4.18 (the current release in that
> > branch), you would be best advised to resign at once, before you get
> > blamed for the train wreck that is inevitably in this system's
> > future.
>
> Done.
>
> Now, how are you on giving advice to improve my love life? :-)

Don't spend your time reading and replying to open source mailing lists?
;)

Joshua D. Drake


>


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